Maggie’s The whole nine yards....

Also "Balls to the Wall" airplane throttles had balls on them. If you wanted full power you put the "Balls to the Wall".

An older version refers to the ball shaped flyweights on centrifugal governors used on steam powered machinery to control speed, “balls to the wall” or “balls out”referred to the machine operating at its highest speed, where the flyweights were completely extended, all the way “out” or “to the wall” which usually shut a steam supply valve or closed a throttle to slow the machine down again.